Dynamoelectric machines such as motors and generators and other rotating machines such as gears and bearing systems are widely employed in industrial and commercial facilities. These machines are relied upon to operate with minimal attention and provide for long, reliable operation. Many facilities operate several hundred or even thousands of such machines concurrently, several of which are integrated into a large interdependent process or system. Like most machinery, at least a small percentage of such equipment is prone to failure. Some of these failures can be attributed to loss of lubrication, incorrect lubrication, lubrication breakdown, or lubrication contamination.
Depending on the application, failure of a machine in service can possibly lead to system or process latency, inconvenience, material scrap, machinery damage, hazardous material cleanup, and even a dangerous situation. Thus, it is desirable to diagnose machinery for possible failure or faults early in order to take preventive action and avoid such problems. Absent special monitoring for certain lubrication problems, a problem may have an insidious effect in that although only a minor problem on the outset, the problem could become serious if not detected. For example, bearing problems due to inadequate lubrication, lubrication contamination or other causes may not become apparent until significant damage has occurred.
Proper lubrication facilitates extension of machinery life. For example, when motor lubricant is continuously exposed to high temperatures, high speeds, stress or loads, and an oxidizing environment, the lubricant will deteriorate and lose its lubricating effectiveness. The loss of lubricating effectiveness will affect two main functions of a lubrication system, namely: (1) to reduce friction and (2) to remove heat. Continued operation of such a degraded system may result in even greater heat generation and accelerated system degradation eventually leading to substantial machinery damage and ultimately catastrophic failure. To protect the motor, the lubricant should be changed in a timely fashion. However, a balance must be struck—on one hand it is undesirable to replace an adequate lubricant but on the other hand it is desired to replace a lubricant that is in its initial stages of breakdown or contamination prior to occurrence of equipment damage. As each particular application of a lubricant is relatively unique with respect to when the lubricant will breakdown or possibly become contaminated, it becomes necessary to monitor the lubricant.
Lubricity can be defined as “an ability of a lubricant to reduce friction between moving, loaded surfaces.” Prior to a mandated reduction in the sulfur content of diesel fuels in the early 90's, no acceptable measurement of lubricity of a fluid was defined. Reduction of sulfur in diesel fuels typically is accomplished via hydro heating, which inadvertently removes lubricating elements from the fuels. Such reduction of sulfur (and thus lubricating elements) has caused premature equipment breakdowns and, in some cases, catastrophic failure. Thus, a demand arose for a system and/or methodology for testing for lubricity of a fluid. Laboratory procedures and measures of lubricity were defined and incorporated into ASTM standards. Such procedures include the Standard Test Method for Evaluating Lubricity of Diesel Fuels by the Scuffing Load Ball-on-Cylinder Lubricity Evaluator (SLBOCLE), the Test Method for Evaluating Diesel Fuel Lubricity by an Injection Pump Rig, the Standard Test Method for Evaluating Lubricity of Diesel Fuels by the High-Frequency Reciprocating Rig (HFRR), and other laboratory testing procedures.
Unfortunately, performing the testing methods described above requires expensive, bulky equipment. Furthermore, the ASTM testing methods require a substantial amount of time for completion, and moreover require operator intervention. More importantly, these tests must be done off-line in a laboratory or bench-top setting. They cannot be done on-line, in real time as the machinery operates. It is to be understood, however, that no standard of lubricity presently exists—only disparate procedures for testing lubricity. The measurements obtained via employing the ASTM testing methods are error-prone due to complexity of such testing procedures, and reproducing the measurements for verification purposes is difficult due to an amount of time required for obtaining a measurement. Moreover, the laboratory testing procedures do not account for an environment in which a lubricant will be employed. For instance, surface coating of metallic parts within a machine can impact an ability of a lubricant to effectively mitigate wear between two moving components. Also, a fluid's ability to carry particular particles within an operating environment can impact lubricity of the fluid. With a continuing trend towards limiting the amount of sulfur present in fuels and lubricants, an in situ sensor that continuously monitors lubricity of a fluid can mitigate breakdown and catastrophic failure of machinery.
In view of at least the above, there exists a strong need in the art for a system and/or methodology facilitating continuous in situ measurement and analysis of parameters relating to fluid lubricity, and a system and/or methodology for maintaining such fluids.